I'd say it's based on levels of success, but then I'm not familiar with the old opposed rules, just the new mrq & brp ones.
If you are a warrior trained to fight with sword and shield in chainmail, it would be natural that you parried instead. The primitive warrior with loincloth and spear should be a better dodger I think.
With a heavy armor, the dodge skill gets to powerfull, as it will downgrade specials and criticals. Then it becomes much better than parries. With some punishing ENC rules, it would be good for those in light armor. The ENC rules would have to be tweaked so that you would prefer parry with heavy armor, but making dodge a viable alternative for those with light or none armor - maybe the minus should be given based on the type of armor instead of ENC itself.
2 free attacks for a critical dodge vs. a fumbled attack might be to much. Yup, I'll lower that to one. The attacker will have to roll on the fumble table in addition, so that should be enough.
I'm going with criticals at 1/100th of skill (rounded up), specials at 1/10th of skill and fumbles at above 91%+1/10th of skill (00 always a fumble), so fumbles will happen more often than the new default (with upgrading of your foes attack if you fumble the dodge against him).
SGL.